1. Field of the Invention
This invention pertains generally to medical apparatus for performing endocardial mapping and, more specifically, to endocardial mapping apparatus having a basket assembly with an array of electrodes thereon.
2. Description of Related Art
Catheters have been provided with basket assemblies on the distal end for performing endocardial mapping. These basket assemblies are formed from a plurality of elongate flexible circumferentially-spaced arms which substantially engage the endocardium and permit blood in the heart to flow therethrough. The arms have a plurality of longitudinally-spaced electrodes thereon which are electrically connected to a multiplexer chip. In some of these basket assemblies, for example the basket assemblies of application Ser. No. 08/044,255 filed Apr. 7, 1993, U.S. Pat. No. 5,327,889 filed Dec. 1, 1992 and U.S. Pat. No. 5,156,151 filed Feb. 15, 1991, the spacing between the arms is larger than would be desired for mapping purposes. In addition, there have been difficulties in effectively ablating with the small low mass electrodes of these arms. Performing ablations with the mapping electrodes also enhances the complication of the multiplexer chip. Because of the foregoing, there is a need for a new and improved endocardial mapping apparatus which overcomes the above named disadvantages.